Mace has been vocal in its criticism of the HS2 saga, calling the procurement process “seriously flawed” after a whistleblower alerted Mace to the possibility of a conflict of interest regarding HS2’s former chief of staff Chris Reynolds.

Mace had submitted written evidence to the Transport Committee ahead of a session last month, claiming HS2 had "consistently misled taxpayers" and that scoring of the bids for the £170m development partner contract “was geared to favour CH2M” and “to favour American companies”.

“My hope is that organisations do not use the courts gratuitously,” Grayling said. “If you have a legitimate grievance we will address it, but please do not use the courts without good grounds because that does no favours to anyone.”

A Mace spokesperson said:

Despite the flawed process, we have decided that the importance of the scheme to the national interest, particularly the North of England, outweighs our drive for taking action.

It is imperative that HS2 now focus their attention on delivering this essential project both on time and in budget.

“We take some comfort from the knowledge that HS2 has conceded its failings and will introduce more stringent processes for future procurement,” Mace said. “We will be meeting with the Secretary of State for Transport shortly to ensure he fully understands our perspective, and to seek further reassurances on how the process will be improved going forward.”